Author Topic: Need some advice on Big Bore'ing engine.  (Read 1165 times)

stejospot

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Need some advice on Big Bore'ing engine.
« on: May 08, 2012, 09:28:16 PM »
So the engine on my People 150 completely blew this past weekend.

The guy at the shop gave me all the options... replace camshaft and other parts... completely buy a new engine... all of them came to about the same price point: between $300-400

and THEN he said, "or...for that price, we could just throw in a GY6 with a big bore kit and bump it up to about 180cc."

What!?  30 more cc's for the same price?

I've heard about these kits, but don't know anything about them. But I won't lie... having an extra 30cc's for about the same price as getting a new OEM engine definitely catches my interest.

Do these big bore kits really boost performance? If so, are there any big risks of putting them on a bike designed for 150 displacement? I could use some insight!

Thanks.

Stejospot
2009 Espresso 150

MikeKymco

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Re: Need some advice on Big Bore'ing engine.
« Reply #1 on: May 26, 2012, 08:52:20 PM »
I want to know too.  Subscribed.

zombie

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Re: Need some advice on Big Bore'ing engine.
« Reply #2 on: May 27, 2012, 12:05:22 AM »
I posted this one before. It all depends on the quality of the BBk as to how long it will last. Some are good, and some crap! . You NEED to have steel valve seats, and a very good mechanic. In 50cc scoots changing jugs is close to 100% displacement increase. In the 150 to 180 swap it is more like 20%. The performance is similar but torque is increased. You will feel a better pull but not much else. I am not trying to deffer you but let you know the increase is not major, and the quality of parts/install will make or break the end result. Stadium Yamaha gives us a GREAT discount so I would lean toward getting the OEM parts, and have your mechanic install them. You may save more than money going this way.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

MikeKymco

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Re: Need some advice on Big Bore'ing engine.
« Reply #3 on: May 30, 2012, 02:20:12 AM »
Thanks, Zombie.  That's disappointing, but not surprising.  And sounds like excellent advice, sticking with known quality parts.

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